St Mary's School was founded by the
Institute of the Blessed Virgin Mary (IBVM). The school chapel was built in 1885 and funded by Cecilia Marshall, and the First Mass was celebrated there on 2 July 1896. The Chapel is dedicated to
Our Lady of Humility and
St Cecilia. It was consecrated by Bishop
John Baptist Cahill in 1906. Since 1984, it has been run by the St Mary's School Ascot Trust. In 1998 the school had its first lay Headmistress, Mrs Mary Breen. In 2006, the school opened its new sports centre, named the Orchard Centre after the Catholic family from which the school's two previous headmistresses came. The Centre was opened by ballerina
Darcey Bussell. A Performing Arts Centre has also been built named the Rose Theatre. It opened in April 2009. In 2018, the school inaugurated its new Upper Sixth (Year 13) Courtyard: new boarding houses area for girls. ==Curriculum==